The field of unmanned aerial vehicles (UAVs) includes attempts during the American civil war to attack targets by means of unmanned balloons carrying explosive charges. These attempts were generally unsuccessful. During WWI, anti-aircraft gunnery target “drones” were controlled by radio. During WWII, the Japanese used the same balloon bomb technique against the continental United States, resulting in a few deaths. Also during WWII, an Allied program “Operation Aphrodite” attacked surface targets with B-17 bombers converted into drones loaded with explosives. Guidance of the drone B-17s included radio control by a remote operator who viewed a television images from television cameras mounted in the aircraft. In the same general time period, other unmanned aerial vehicles included the German V1 weapons, which were generally unguided in that they were not directed at specific targets, although they were controlled in that they were attitude-stabilized and followed a heading before running out of fuel and crashing. The V2 weapon was also stabilized, and somewhat directionally controlled. More recently, unmanned aerial vehicles have included various missiles such as surface-to-air, air-to-surface, and air-to-air missiles, which are often wholly or partially autonomous, especially in the final attack phase. The Tomahawk “cruise” missile is preprogrammed with a course, and follows the course using Global Positioning Satellite (GPS) positioning and comparison of local sensor data with a preprogrammed digital “map.”
Unmanned aerial vehicles have more recently been used for tactical surveillance. This type of vehicle includes the Firebee of Vietnam-war vintage, Hunter, and Pioneer. The Predator is currently in use for surveillance and for other uses. The Predator uses a four-cylinder engine, has a wing span of 48 feet, a length of 27 feet, and a takeoff weight of 2250 lb. It can operate at altitudes of up to 25,000 feet, loiter for up to 40 hours, and in its surveillance role can carry a color video camera, a synthetic-aperture radar, and other sensors. In one of its roles, it can carry and launch Hellfire antitank missiles. The Global Hawk follows the Predator, and provides additional capability, such as a range of more than 12,000 nautical miles and altitudes up to 65,000 feet. However, with a wingspan of 116 feet, length of 44 feet, and 26,000 lb. takeoff weight, it is larger than the Predator. This increased size and weight by comparison with the Predator results in a loiter duration of 24 hours. The Fire Scout is a recently developed reconnaissance and surveillance UAV based on a commercial manned helicopter. The Fire Scout is capable of remote control and of autonomous takeoff and landing from ships or prepared landing sites, and can identify and designate targets. Recent work has been directed toward mounting weapons on the Fire Scout.
Ground troops at the small unit level cannot directly take advantage of information resulting from surveillance by unmanned aerial vehicles (UAVs) such as Predator and Global Hawk. However, ground troops would benefit from availability of small reconnaissance UAVs which could examine their local area under the control of the troops themselves, to report directly to those troops. UAVs for such use suffer from various problems, including that they are regularly destroyed or lost during operation, can be damaged by physical abuse, dirt or water, at least some of which tend to be omnipresent in a combat situation. They also tend to have limited range or loiter time, and often require special training to operate. The Dragon Eye backpack reconnaissance transportable UAV is less than two feet long, electrically powered with two propellers, and can be hand- or bungee-launched. Its weight is about 5.5 lb. Its range or loiter time is limited by the capacity of the batteries that can be carried.
Improved or alternative unmanned aerial vehicles are desired.